Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to an apparatus and method for improving the performance of a user equipment handover during a data call.
Background
Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems, and orthogonal frequency division multiple access (OFDMA) systems.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple user equipment devices (UE). Each UE communicates with one or more base stations, such as a Node B, evolved Node B (eNB), or other access point, via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the UEs, and the reverse link (or uplink) refers to the communication link from the UEs to the base stations. This communication link may be established via a single-in-single-out, multiple-in-single-out or a multiple-in-multiple-out (MIMO) system.
UEs can establish calls with other UEs via a base station. This can include a voice call (e.g., using a circuit-switched network), a data call using voice over internet protocol (VoIP), VoIP over LTE (VoLTE) or other packet-switched technology, and/or the like. When a UE is involved in a data call, the base station can configure a radio connection/bearer carrying the call traffic using a connected mode discontinuous reception (CDRX) policy to ensure good call performance and improved battery life at the UE. Such policies allow the UE to remain in connection with the base station while powering down its radio components (and/or processing components) to conserver batter power during one or more time periods (known as sleep periods or OFF durations). The base station can pre-configure UE's sleep periods in anticipation of predictable arrival of the frames related to the data call.
In addition, the wireless network can configure semi-persistent scheduling for the UE in a data call that guarantees apriori grants for the transmission and reception of data call frames. This can reduce the amount of signaling generated and the amount of power spent in making ad hoc grant requests. For example, the predictable arrival of data call frames can be used to configure the apriori grants. In general, CDRX and scheduling schemes that guarantee apriori grants, such as semi-persistent scheduling, can improve resource utilization for data calls at a UE. Such optimizations, however, can disrupt or delay transmission of data call packets during handovers.